Brain Death Diagnosis_group 3
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Transcript of Brain Death Diagnosis_group 3
Determination of
Brain Death
Cleopatra Motsoari
Jenny Koo
ConceptsConcepts of Brain deathof Brain death
• Whole brain Irreversible cessation of all functions of the brain, including the brainstem.
• Neocortical Permanent cessation of the neocortex function. Clinical examination is used & the presence of brain stem activity is considered irrelevant.
• Brainstem Irreversible loss of the capacity of consciousness combined with the irreversible loss of breathing. No instrumental tests are required.
Elements necessary for BDDElements necessary for BDD
• It is important to know the Pathophysiology
• Clinical exam must be done by a well trained doctor– Pupil reflex– Corneal reflex – Painful stimulus over trigeminal – Oculo-vestibular reflex– Gag reflex– Cough reflex– Apneic test
• Complementary tests
Pre-requirementsPre-requirements
• Comatose Patient
• A Diagnosis of Neurological Injury
• Exclude Reversible Conditions– Drug,--Sedation or muscle relaxant– Hypothermia ( temp < 35oc), – Metabolic and electrolyte
disturbance – Arterial hypotension
• Exclude cervical spinal injury or other facial trauma that may invalidate the test result
• Ability to perform apnea testing
Pupil Reflex Corneal ReflexCorneal ReflexPupils show no response to bright light No response to a firm touch of the
cornea
Pain StimuliPain Stimuli
Look for Response in Cranial Nerve Distribution
Oculo-vestibular Oculo-vestibular
Not at Angle of Jaw
Slow injection of 20 ml ice-cold water into both external auditory meatus
Gag Reflex
• Stimulate the posterior pharyngeal wall with a tongue depressor bilaterally
• No gag response
• If patient is orally intubated, the gag reflex may be difficult to discern
Cough or tracheal Reflex
• Stimulate the tracheo-bronchial wall with a soft suction catheter
• No cough response
• Moving the endotracheal tube back and forth is NOT adequate
• The efferent for this reflex is via the phrenic nerve and can’t be assessed in patients with high cervical spinal cord injury
Apnea Test• ONLY proceed if all the above
reflexes are absent
• Pre-oxygenation– Oxygen cannula at 6L/min at
level of carina– T-Piece or CAPA circuit
connected to ET tube
• PaCO2: raised by 3-4 mmHg per minutes
• Watch out for cardiac dysrhythmias and systemic hypotension
Compatible with BDCompatible with BD
• Spinal reflex
• Sweating, blushing, tachycardia
• Normal Blood pressure without need for inotropic support
• Absence of diabetes insipidus (DI)
Incompatible with BDIncompatible with BD
• Decerebrate or decorticate posturing
• True extensor or flexor motor responses to painful stimuli
• Seizures
Spinal reflexSpinal reflex
Can be spontaneous or elicited by stimulation, including painful stimulus applied to limbs or sternum
• Extension-pronation of upper limbs or non-specific flexion of lower limbs’
• Undulating toe reflex• Lazarus sign• Deep tendon reflexes• Plantar responses, either flexor or extensor• Respiratory –like movement without significant tidal volume• Head turning
Discussion
Is my patient really dead?
What should I do if the clinical test can’t What should I do if the clinical test can’t complete?complete?
No brainstem reflexes no body movement
• Body movements generated by the spine can occur i.e. spinal reflexes
• Slow body movement, facial twitching, Babinski reflex, deep tendon, abdominal and cremasteric reflexes
• Sweating & blushing are not exclude BD
If patient is unstable during Apnea test?
• Systolic blood pressure < 90 mmHg
• Arterial oxygen desaturation
• Cardiac dysrhythmia
• STOP the test and reconnect the patient back to ventilator
• Confirmatory test may be required at discretion of physician
When to use confirmatory tests?• Cause of injury/death is unknown
• Presence of confounding factors e.g. drugs, hypothermia
• Complete clinical exam cannot be performed
• Conditions precluding apnea test e.g. cardiovascular instability, severe hypoxemic respiratory failure
• Serve to replace or expedite performance of a required repeat second clinical exam
• Transplant opportunities
Common Confirmatory Tests• Electrophysiological tests:
– EEG– Evoked potentials
• Cerebral blood flow evaluation tests:
– Conventional contrast angiography
– Transcranial Doppler ultrasonography
– Radionuclide brain scintigraphy Radionuclide angiography Brain SPECT scintigraphy
Who should perform the test?
• A skilled & knowledgeable doctor
• There must be no conflict of interest • The person authorizing removal of tissues and the person
removing tissues MUST NOT be responsible for determining brain death
Summary
• Six clinical test for brain-stem reflexes
• Confirmatory Tests
• It is the principle requisite for organ donation and
transplant
8-minutes video on Brain Death Diagnosis8-minutes video on Brain Death Diagnosis
“Establishing the diagnosis of brain death has never been easy for most physicians”
Dr. Mark S. George
Thank you